A major open ? and very important ? question in cognitive neuroscience is: how and where are decisions made? Based on experimental work using a motion discrimination task, it is thought that perceptual decisions evolve within visuomotor regions of the brain controlling the generation of action. Where in the brain are decisions based on form computed? Are the principles gleaned from studying motion decisions applicable to form-based decisions? How do memories (mediated by the medial temporal lobe system) interact with perceptions to guide choices? We address these questions in four aims. In Aim 1, we will determine performance accuracy and sensitivity of subjects in novel perceptual decision-making tasks that rely on form information. We will test the hypothesis that subjects show evidence of a decision-to-bound process in the performance of a form-based, perceptual decision-making task. In Aim 2, we will determine the role of V4 extrastriate cortex in the perception of Glass patterns and in a novel perceptual decision-making task that relies on form discrimination. We will determine the relationship between neuronal activity in extrastriate cortical area V4 and behavioral performance in a form-based perceptual task in the same way that MT neuronal activity was characterized for motion perception. By building on our previous work, in Aim 3, we will determine the role of the superior colliculus in form-based perceptual decision-making and in Aim 4, we will determine whether the basal ganglia play a role in conveying memory information to motor circuits to guide form-based decisions under conditions of sensory uncertainty. The results of our experiments will shed new light on decision-making processing in visual areas of the brain and may provide a framework for understanding enigmatic symptoms seen in a number neurological and neuropsychiatric diseases involving the basal ganglia.